DTE/DCE cable for lab?

ehnde

Do I need a DTE and DCE cable to simulate a WAN connection? I'm about 80 pages in Odom's book and he mentions doing this. Or can I connect my two routers using T1 DSU/CSU's on each router connected with a crossover cable?

Sorry if this is a silly question, I need to know if it's necessary to buy more equipment. One month from now I'll look back on this and think...duh! Obvious!

Greenmet29

I'm not 100% sure on this, but a CSU/DSU supplies clocking, and unless there is a way to disable clocking on the csu/dsu(basically making it the DTE side), I don't think there is any way to make this work. The reason is that the DCE side of the cable supplies the clocking and the DTE side listens for clocking and tries to syncronize with the DCE.

Hopefully someone else will give their 2 cents too, if i'm right, it will boost my confidence that I might actually pass the CCENT that i'm taking in a few weeks.

ehnde

The book mentioned setting the clock rate with a certain command...something like

clock rate

So if there is a need to set the clock rate, I'd think it wasn't set to begin with, meaning it could be set on one end and not the other. I've read another 20 pages and still haven't figured it out.

ehnde

I've found out it can be done, but requires a crossover cable with a different pinout from a standard crossover cable. Answered my own question, no DCE/DTE required

Greenmet29

Sweet! Can you post details on the pinout used becuase I have 2 csu/dsu cards (I think) and I could do the same thing if needed.

ehnde

This is beyond my current limitations, but I found the pinout here How to Make a T1 Cross Over Cable.  T1 Cross over Cables. (I could make the cable, but can't yet configure the routers in this way).

sthompson86

ehnde wrote: »

Or can I connect my two routers using T1 DSU/CSU's on each router connected with a crossover cable?

Thats what I opted to do, for CSU cards were cheaper than full on serial cards, and I can make the cross over cables.

dandix

Pin out for T1's are 1&2 / 4&5.. So to make a x-over cable it would be pin's: 1 to 4 & 2 to

dandix

Sorry iPhone cut me off.. Pin's are 1 to 4, and 2 to 5.. Also found this site that has a picture.. T1 Crossover Cable, Loopback Plug - Fonality Knowledge Base

hermeszdata

Once you have the correct cable and connect between the two routers, you will see both interfaces in the UP/UP state.


On DCE Router

conf t
int s{slot/sub-slot}
ip address *.*.*.* #.#.#.#
clock rate {Clock rate in BPS}

On DTE Router

conf t
int s{slot/sub-slot}
ip address *.*.*.* #.#.#.#

The above assumes that the interfaces are not administratively DOWN.

There are other commands under the DUS-T1 interface CLI. Just use the help feature to see what they are and paly with the options.

JOhn